True, but my comment was in response to GPUs typically using GDDR6 over wide LPDDR5. I figured it was mainly cost.
You are correct that the main reason that GPU use GDDR is reduced cost. But they also don't care that much about power consumption, not even on laptops, since the dGPU can be disabled in regular operation, so they can simply pick the cheapest option that lets them meet their performance targets. GDDR was never an option for Apple, because you can't use it as a portable machine's system memory.